I have a 91 bronco pushing 35s and I wanted to get some advice on regearing it for some more power

 

most will tell you 4.56, myself I went with 4.88's to have a little extra rpm's and love the setup both onroad and off.

what motor/trans do you have.

 

I have a 5.8/351 windsor and an automatic e40d

 

I have a 5.8/351 windsor and an automatic e40d

 

4.88 best bet I agree

 

Engine RPM = (Speed * Transmission Gear Ratio * Final Drive * 336) / Tire Diameter

The E4OD's gears are:

1st: 2.71
2nd: 1.54
3rd: 1.00
OD: 0.71

Use that to find out what RPMs your engine will be at for a given speed and see which gearing you'd be most comfortable with.

For example, if you want to go 65 in overdrive:

4.88
RPM = (65 * 0.71 * 4.88 * 336) / 35
RPM = 2160

4.56
RPM = (65 * .71 * 4.56 * 336) / 35
RPM = 2020

etc.

Play around with it for 1st / 2nd gear getting up to speed. Going 35 in town, etc.

If you're looking for more power, remember that, simply, the more aggressive your gearing, the more power you'll have. So there are more factors than just "more power". Some 5.14s, or even 5.71s are going to net you even more power yet.

You need to decide what you want to do with the vehicle, where you want the power, and where you want to draw the line. Is it a rock crawler? Do you want to use it on the freeway? Etc.